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Revision 1.8 - (hide annotations) (download)
Sun Jan 18 01:32:35 2004 UTC (10 years, 8 months ago) by liquidx
Branch: MAIN
Changes since 1.7: +9 -5 lines
fix ROOT issues for livecd building

1 liquidx 1.1 # Copyright 1999-2003 Gentoo Technologies, Inc.
2     # Distributed under the terms of the GNU General Public License v2
3 liquidx 1.8 # $Header: /home/cvsroot/gentoo-x86/eclass/alternatives.eclass,v 1.7 2003/11/24 10:57:06 liquidx Exp $
4 liquidx 1.1
5     # Author : Alastair Tse <liquidx@gentoo.org> (03 Oct 2003)
6     # Short Desc: Creates symlink to the latest version of multiple slotted
7     # packages.
8     #
9     # Long Desc:
10     #
11     # When a package is SLOT'ed, very often we need to have a symlink to the
12     # latest version. However, depending on the order the user has merged them,
13     # more often than not, the symlink maybe clobbered by the older versions.
14     #
15     # This eclass provides a convenience function that needs to be given a
16     # list of alternatives (descending order of recent-ness) and the symlink.
17     # It will choose the latest version if can find installed and create
18     # the desired symlink.
19     #
20     # There are two ways to use this eclass. First is by declaring two variables
21     # $SOURCE and $ALTERNATIVES where $SOURCE is the symlink to be created and
22     # $ALTERNATIVES is a list of alternatives. Second way is the use the function
23     # alternatives_makesym() like the example below.
24     #
25     # Example:
26     #
27     # pkg_postinst() {
28     # alternatives_makesym "/usr/bin/python" "/usr/bin/python2.3" "/usr/bin/python2.2"
29     # }
30     #
31     # The above example will create a symlink at /usr/bin/python to either
32     # /usr/bin/python2.3 or /usr/bin/python2.2. It will choose python2.3 over
33     # python2.2 if both exist.
34     #
35     # Alternatively, you can use this function:
36     #
37     # pkg_postinst() {
38     # alternatives_auto_makesym "/usr/bin/python" "/usr/bin/python[0-9].[0-9]"
39     # }
40     #
41     # This will use bash pathname expansion to fill a list of alternatives it can
42     # link to. It is probably more robust against version upgrades. You should
43     # consider using this unless you are want to do something special.
44     #
45     ECLASS="alternatives"
46     INHERITED="$INHERITED $ECLASS"
47    
48     # automatic deduction based on a symlink and a regex mask
49     alternatives_auto_makesym() {
50 liquidx 1.6 local SYMLINK REGEX ALT myregex
51     SYMLINK=$1
52 liquidx 1.1 REGEX=$2
53 liquidx 1.6 if [ "${REGEX:0:1}" != "/" ]
54     then
55     #not an absolute path:
56     #inherit the root directory of our main link path for our regex search
57     myregex="${SYMLINK%/*}/${REGEX}"
58 liquidx 1.1 else
59 liquidx 1.6 myregex=${REGEX}
60     fi
61 liquidx 1.8
62 liquidx 1.6 # sort a space delimited string by converting it to a multiline list
63     # and then run sort -r over it.
64 liquidx 1.8 # make sure we use ${ROOT} because otherwise stage-building will break
65     ALT="$(for i in $(echo ${ROOT}${myregex}); do echo ${i#${ROOT}}; done | sort -r)"
66 liquidx 1.6 alternatives_makesym ${SYMLINK} ${ALT}
67 liquidx 1.1 }
68    
69     alternatives_makesym() {
70     local ALTERNATIVES=""
71 liquidx 1.6 local SYMLINK=""
72     local alt pref
73 liquidx 1.8
74 liquidx 1.1 # usage: alternatives_makesym <resulting symlink> [alternative targets..]
75 liquidx 1.6 SYMLINK=$1
76 liquidx 1.8 # this trick removes the trailing / from ${ROOT}
77     pref=$(echo ${ROOT} | sed 's:/$::')
78 liquidx 1.1 shift
79     ALTERNATIVES=$@
80    
81     # step through given alternatives from first to last
82     # and if one exists, link it and finish.
83    
84     for alt in ${ALTERNATIVES}; do
85 liquidx 1.6 if [ -f "${pref}${alt}" ]; then
86     #are files in same directory?
87     if [ "${alt%/*}" = "${SYMLINK%/*}" ]
88     then
89     #yes; strip leading dirname from alt to create relative symlink
90 liquidx 1.8 einfo "Linking ${alt} to ${pref}${SYMLINK} (relative)"
91 liquidx 1.7 ln -sf ${alt##*/} ${pref}${SYMLINK}
92 liquidx 1.6 else
93     #no; keep absolute path
94 liquidx 1.8 einfo "Linking ${alt} to ${pref}${SYMLINK} (absolute)"
95 liquidx 1.7 ln -sf ${pref}${alt} ${pref}${SYMLINK}
96 liquidx 1.1 fi
97     break
98     fi
99     done
100    
101     # report any errors
102 liquidx 1.6 if [ ! -L ${pref}${SYMLINK} ]; then
103     ewarn "Unable to establish ${pref}${SYMLINK} symlink"
104     else
105     # we need to check for either the target being in relative path form
106     # or absolute path form
107     if [ ! -f "`dirname ${pref}${SYMLINK}`/`readlink ${pref}${SYMLINK}`" -a \
108     ! -f "`readlink ${pref}${SYMLINK}`" ]; then
109     ewarn "${pref}${SYMLINK} is a dead symlink."
110     fi
111 liquidx 1.1 fi
112     }
113    
114     alternatives_pkg_postinst() {
115     if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
116     alternatives_makesym ${SOURCE} ${ALTERNATIVES}
117     fi
118     }
119    
120     alternatives_pkg_postrm() {
121     if [ -n "${ALTERNATIVES}" -a -n "${SOURCE}" ]; then
122     alternatives_makesym ${SOURCE} ${ALTERNATIVES}
123     fi
124     }
125    
126     EXPORT_FUNCTIONS pkg_postinst pkg_postrm

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